1. Field of the Invention
This invention relates to a covering material and more specifically to a protective covering material for forming a film or coat on the skin or wound surface.
2. Description of the Prior Art
It is effective in the treatment of wounds, especially burn, to cover the wound surface with a membranous protective covering material so that intrusion of bacteria from without, hence bacterial infection through the wound surface, may be inhibited. For practical purposes, such as covering material is required to be
(i) non-irritating and nontoxic to the skin or wound,
(ii) permeable to the exudate from the burnt skin to the extent that the exudate may not accumulate beneath the covering coat,
(iii) not sticking to the wound surface, and
(iv) easily removable, when necessary.
As a covering material having such characteristics, there is known a plastisol consisting of a hydrophilic, water insoluble polymer powder and a high boiling plasticizer or solvent therefor (U.S. Pat. No. 3,577,516). This materials, as is disclosed in said U.S. patent, is applied to the skin to be protected in the following way: First, the liquid, high boiling plasticizer (or solvent) is applied to the skin by spraying, and then the polymer powder is sprayed onto that skin. By this procedure, the polymer powder and the high boiling plasticizer (or solvent) are mixed on the skin and give a plastisol, which forms a film to protect the skin. However, in using such a plastisol in the field of clinical medicine, for example in the treatment of thermal burn, the time required for formation of such a plastisol film on the skin becomes a problem. In the case of the covering material disclosed in the above-cited U.S. patent, it takes about 30 minutes to form a film thereof on the skin, while the clinician cannot do subsequent treatments but have to wait for completion of the film formation. Therefore such a covering material has been thought to be unfavorable and some measure for reducing the film formation time has been waited for.